This invention relates to a refrigeration system suitable for use in a vehicle, and more particularly, to an improvement enabling the use of both an air conditioner to cool the vehicle's passenger compartment and a refrigerator disposed within the vehicle.
Generally, the small-volume refrigerator which is disposed in the compartment of a vehicle is cooled by a part of the cooled air which is conducted from a refrigeration system for the vehicle air conditioner. However, in this construction of the air conditioner and refrigerator, the location of the refrigerator is restricted, because the conduit arrangement from the air conditioner must be considered. Furthermore, the temperature in the refrigerator depends on the operating condition of the air conditioner; therefore, the refrigerator compartment is often not cooled sufficiently to produce ice. This is due to the fact that the interior of the refrigerator is cooled by only that part of the cooled air which passes through the refrigerator section of the vehicle air conditioner.
One solution is to provide the refrigeration system with two evaporators connected in parallel to achieve independent cooling in both the passenger compartment and the refrigerator compartment. This refrigeration system will be described, hereinafter, with reference to FIG. 1.
FIG. 1 shows a diagramatic refrigerant circuit which comprises a compressor 1, a condenser 2, a receiver and dryer 3 and two evaporators 4 and 5, connected to form a closed loop refrigeration circuit. One of the two evaporators 4 is disposed in a duct of the vehicle's air conditioner to cool the passenger compartment, and the other evaporator 5 is disposed in a refrigerator to cool the refrigerator compartment. Evaporators 4 and 5 are connected in parallel, and flow of the refrigerant through them is controlled by the magnetic valves 6 and 7 disposed on the inlet side of evaporators 4 and 5, respectively. Expansion valves 8 and 9 are also disposed on the inlet side of evaporators 4 and 5, respectively, with expansion valve 8 (connected to air conditioning evaporator 4) being controlled in accordance with the refrigerant temperature at the outlet side of evaporator 4. A check valve 10 is disposed on the outlet side of refrigerator evaporator 5.
In this construction of the refrigerant circuit, the circuit requires two magnetic valves and two expansion valves to control the operation of the two evaporators. Therefore, the refrigerant pipe arrangement is complicated, and the cost of the system excessive.